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Abstract:

By analyzing consecutive timestamps at which the battery cell is fully
charged in two or more previous time intervals, the charging control
method utilizes these consecutive timestamps of a sub-section of each
time interval as a charging control way to the rechargeable battery in a
present time interval. The charging process of the rechargeable battery
in corresponding timestamps of the present time interval is limited to a
specific proportion of the fully charged capacity of the battery cells.
In such way, the rechargeable battery may have fewer chances to be fully
charged at some less used time, which substantially increases the life of
the battery.

Claims:

1. A charging control method of rechargeable battery, wherein a
rechargeable battery comprises a battery cell and a control unit in
electrical connection with the battery cell, the method comprising using
the control unit to execute the following steps: charging the battery
cell when a power supply unit is in connection with the battery cell;
recording the relative state of charge (RSOC) of the battery cell for a
plurality of time intervals, each time interval comprising a plurality of
timestamps; and when the RSOC of the battery cell reaches the full charge
capacity (FCC) for n consecutive timestamps comprised by a first
sub-section of an Nth time interval and for n consecutive timestamps
comprised by a second sub-section of an N+1.sup.th time interval, where
the second sub-section corresponds to the first sub-section, the control
unit limiting the power supply unit to charge the battery cell to not
exceeding a specific proportion of the FCC at n consecutive timestamps
comprised by a third sub-section of an N+2.sup.th time interval, where
the third sub-section corresponds to the first sub-section and the second
sub-section; wherein N is a positive integer and n is a positive integer
larger than 1.

2. The charging control method of claim 1, wherein each Nth time interval
is a day and each Nth time interval comprises 24 timestamps.

3. The charging control method of claim 1, wherein n is an integer larger
than 3 and smaller than 24.

4. The charging control method of claim 1, further comprising step: the
control unit allowing the power supply unit to charge the battery cell to
the FCC at the timestamps of the N+2.sup.th time interval that are not
comprised by the third sub-section.

Description:

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The invention relates to a charging control method of a
rechargeable battery, and more particularly, to a charging control method
capable of prolonging the battery life.

[0003] 2. Description of the Prior Art

[0004] Considering the convenience of using an electronic system and the
capacity requirement of the power supply, most electronic systems adapt
rechargeable battery as the source of its power supply, in which the
batteries using lithium polymer as core substance are regarded as the
most mature products with high capacity density specification. The
rechargeable battery is primarily charged by a power supply unit or via
an AC adapter from an electronic system where the rechargeable battery is
installed. When the electronic system such as a laptop computer is in
use, with the AC adapter connected, the electronic system usually
consumes power from the power source via the AC adapter instead of from
the rechargeable battery. Once the power from the AC adapter is
disconnected from the electronic system, the rechargeable battery
provides power for the electronic system until the AC adapter with power
is reconnected to both provide power for the electronic system and charge
the rechargeable battery all the way when the rechargeable battery
reaches the full charge capacity (FCC). Such repetitive change between
fully charged state and not fully charged state is very common for the
rechargeable battery. One nature of the rechargeable battery should be
taken care of: the life of a rechargeable battery may be damaged when the
rechargeable battery is connected to the power supply unit and stays
constantly at the 100% fully charged state for a quite a long time.

[0005] On the other hand, some regularity may exist according to how a
user uses the electronic system. For example, the user may plug an AC
adapter to a laptop computer but not use it within a certain period of
time for each day. According to the charging design of the prior art, the
rechargeable battery of the laptop computer may be charged and maintained
at the FCC for at least a couple of hours in the time interval every day,
let's say the couple of hours during the night time. It apparently causes
unrecoverable damage to the rechargeable battery if the charging scheme
of the prior art is adapted.

SUMMARY OF THE INVENTION

[0006] It is therefore an objective for the invention to provide an
intelligent design of charging mechanism in a rechargeable battery to not
overly keep the battery at a 100% fully charged state that may damage the
battery life. The embodiments of the invention provides a charging
control method that allows a battery control unit inside the rechargeable
battery to handle the charging process of the rechargeable battery,
taking into consideration of how an user uses the rechargeable battery,
in an intelligent way. The method also prolongs the battery life in a
substantial scale.

[0007] An embodiment of the invention provides a charging control method
of rechargeable battery. For a rechargeable battery including a battery
cell and a control unit in electrical connection with the battery cell,
the method includes using the control unit to execute the following
steps: charging the battery cell when a power supply unit is in
connection with the battery cell; recording the relative state of charge
(RSOC) of the battery cell for a plurality of time intervals, each time
interval comprising a plurality of timestamps; and when the RSOC of the
battery cell reaches the full charge capacity (FCC) for n consecutive
timestamps comprised by a first sub-section of an Nth time interval and
for n consecutive timestamps comprised by a second sub-section of an
N+1th time interval, where the second sub-section corresponds to the
first sub-section, the control unit limiting the power supply unit to
charge the battery cell to not exceeding a specific proportion of the FCC
at n consecutive timestamps comprised by a third sub-section of an
N+2th time interval, where the third sub-section corresponds to the
first sub-section and the second sub-section. In the embodiment, N is a
positive integer and n is a positive integer larger than 1.

[0008] For the charging control method provided by the embodiment of the
invention, each Nth time interval is a day, each Nth time interval
comprises 24 timestamps, and n is an integer larger than 3 and smaller
than 24.

[0009] Also for the charging control method provided by the embodiment of
the invention, the method further includes step: the control unit
allowing the power supply unit to charge the battery cell to the FCC at
the timestamps of the N+2th time interval that are not comprised by
the third sub-section.

[0010] By analyzing consecutive timestamps at which the battery cell is
fully charged in two or more previous time intervals or days, the
charging control method utilizes these consecutive timestamps of a
sub-section of each time interval as a charging control way to the
rechargeable battery in a present time interval. The charging process of
the rechargeable battery in corresponding timestamps of the present time
interval is limited to a specific proportion of the fully charged
capacity of the battery cells. In such way, the rechargeable battery may
have fewer chances to be fully charged at some less used time, which
substantially increases the life of the battery.

[0011] These and other objectives of the present invention will no doubt
become obvious to those of ordinary skill in the art after reading the
following detailed description of the preferred embodiment that is
illustrated in the various figures and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] FIG. 1 is an illustration of a rechargeable battery applied with a
charging control method provided by the invention.

[0013] FIG. 2 is an illustration of a flow chart of a charging control
method according to the embodiment of the invention.

[0014]FIG. 3 is an illustration of a chart showing an RSOC state of the
rechargeable battery versus time applied with the charging control method
of the invention.

DETAILED DESCRIPTION

[0015] Please refer to FIG. 1, which is an illustration of a rechargeable
battery applied with a charging control method provided by the invention.
A rechargeable battery 10 may be installed on an electronic system, which
is not shown in the figure, as a power supply source for the electronic
system. The rechargeable battery 10 may also be charged by a power supply
unit, which is not shown in the figure, when connected to. The
rechargeable battery 10 includes a control unit 12, a battery set 14, and
a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) circuit
module 20. The control unit 12 is a battery control integrated circuit of
the rechargeable batter 10 and is electrically connected to the battery
set 14 and the MOSFET circuit module 20. The control unit 12 monitors the
battery set 14, detects and takes control of data and the
discharging/charging process of the battery set 14. The battery set 14 is
composed of a plurality of battery cells 141, each connected with one
another in serial way, in parallel way, or in hybrid way. Particularly,
the battery cells 141 are lithium polymer batter cells. The MOSFET
circuit module 20 includes a discharge MOSFET 22 (DXG MOSFET) and a
charge MOSFET 24 (CHG MOSFET), which are controlled and turned on/off by
the control unit 12. When the DXG MOSFET 22 and the CHG MOSFET 24 are
turned on, a charging loop L2 and a discharging loop L1 exist in the
rechargeable battery 10.

[0016] Please refer to FIG. 2, which is an illustration of a flow chart of
a charging control method 100 according to the embodiment of the
invention. The charging control method 100 includes the following steps:

[0017] Step 102: Start;

[0018] Step 104: Charging a battery cell when a power supply unit is in
connection with the rechargeable battery;

[0019] Step 106: The control unit recording the relative state of charge
(RSOC) of the battery cell at a first time interval;

[0020] Step 108: The control unit recording the relative state of charge
(RSOC) of the battery cell at a second time interval;

[0021] Step 110: The control unit obtaining the intersection of two
sub-sections from the first time interval and the second time interval
respectively that have the RSOC of the battery cell reaches the full
charge capacity (FCC);

[0022] Step 112: The control unit limiting the battery cell to be charged
to not exceeding a specific proportion of the FCC at a sub-section, which
corresponds to the intersection obtained in Step 110, of a third time
interval.

[0023] The charging control method 100 of the invention handles the
charging control of the rechargeable battery 100 according to statistic
data of the time the rechargeable battery reaches the full charge
capacity (FCC), and more specifically, the charging control method 100
takes extra control over the charging process of the battery set 14 at
some particular sub-section(s) of the present time interval, according to
the regularity of how a user uses the electronic system, so that the
rechargeable battery 10 may be less kept at 100% fully charged state.
According to this, the rechargeable battery 10 is normally charged once
connected with a power supply unit as described in Step 104, and in Step
106 and Step 108, the control unit 12 keeps a record of the relative
state of charge (RSOC) of the rechargeable battery 10 for a number of
time intervals. More specifically, the time interval will be exemplified
as, but not limited to, 24 hours (or a day) in the embodiments of the
invention, while each different time interval may have a plurality of
timestamps, such as 24 timestamps for each time interval taking one day
as an example. In that, the control unit 12 records the relative state of
charge of the battery set 14 at each of the plurality of timestamps of
each of N time intervals, where N should be regarded as a positive
integer.

[0024] Next in Step 110, the control unit 12 analyzes the a first
sub-section and a second sub-section of a first time interval and a
second time interval respectively, in Step 106 and Step 108 that both
have the RSOC of the battery cells 141 reaches the FCC (or a limited FCC,
which is previously limited by the control unit 12) and obtains a
sub-section from the intersection of the two sub-sections. Finally, the
method performs Step 112 by placing the charging control over the battery
cells 141 at the timestamps in a third sub-section of a third time
interval corresponding to the sub-section of the intersection of the two
sub-sections obtained in Step 110, i.e., the control unit 12 limits the
battery cells 141 only can be charged, if possible, at top to a specific
proportion of the FCC at these timestamps of the third sub-section at the
third time interval. In such way, the rechargeable battery 10 may be less
kept at 100% fully charged state.

[0025] Additionally, the rechargeable battery 10 may be at a charging
state when connected to the power supply unit or at a discharging state,
either discharging to supply power for the electronic system or just
self-discharging, when not connected to the power supply unit at each
timestamp of each time interval. The control unit 12, however, keeps the
records of the RSOC of the battery cells 141 at each timestamp regardless
of at which state the rechargeable battery 10 may be, so the method of
the invention applies to the rechargeable battery 10 whether or not the
rechargeable battery 10 is in connection with the power supply unit. It
also should be noted that the RSOC of the battery cells 141 may have
chance to reach the FCC only when the rechargeable battery 10 is in
connection with the power supply unit and charged.

[0026] Please refer to FIG. 3, which is an illustration of a chart showing
an RSOC state of the rechargeable battery versus time applied with the
charging control method of the invention. In FIG. 3, the total N
consecutive time intervals are exemplified as day 1 to day 5, each
including 24 timestamps. An index is filled in each of the timestamps of
every time interval that records the RSOC of the rechargeable battery 10
and because the charging control method 100 of the invention collects
information on the timestamps that the rechargeable battery 10 reaches
the FCC (or the limited FCC, which is previously limited by the control
unit 12), the index value filled in each timestamp shows only whether the
RSOC reaches the FCC and is either 0 or 1, in which 1 represents that the
RSOC of the rechargeable battery 10 has yet reached the FCC and 0
represents that the RSOC of the rechargeable battery 10 has reached the
FCC (or the limited FCC).

[0027] For example, during the 24 timestamps of a first time interval (day
1), both a sub-section T1 with n consecutive timestamps spanning
from 6 o'clock to 14 o'clock, which means n equals 9, and a sub-section
T4 with n consecutive timestamps spanning from 19 o'clock to 23
o'clock, which means n equals 5, have RSOC of the rechargeable battery 10
at the FCC. Following up during the 24 timestamps of a second time
interval (day 2), both a sub-section T2 with n consecutive
timestamps spanning from 7 o'clock to 16 o'clock, which means n equals
10, and a sub-section T5 with n consecutive timestamps spanning from
20 o'clock to 23 o'clock, which means n equals 4, also have RSOC of the
rechargeable battery 10 at the FCC. From the above data, both a first
sub-section T11 (including 8 consecutive timestamps from 7-14
o'clock) of the first time interval and a second sub-section T21
(including 8 consecutive timestamps from 7-14 o'clock) of the second time
interval may be obtained from the intersection of the sub-section T1
and the sub-section T2. Since the RSOC of the rechargeable battery
10 reaches the FCC at the intersection (8 consecutive timestamps from
7-14) of the two sub-sections T1 and T2 from the first time
interval and the second time interval, a third sub-section T3 of a
third time interval (day 3) that corresponds both to the first
sub-section T11 and the second sub-section T21 and includes 8
consecutive timestamps from 7-14 is the spanning time interval the
control unit 12 limits the power supply unit to charge the battery cells
141 to not exceeding a specific proportion of the FCC, for example, to
80% of the FCC. It should be noted that the 0 index in each timestamp
during 9 o'clock and 14 o'clock of the third time interval means the
battery cells 141 have been charged to a limited FCC, or 80% of the FCC
for example, as mentioned earlier. In such way, the battery cells 141 may
be limited to have been charged to 100% FCC, which results in damage to
the rechargeable battery 10, in the sub-section T3. Also for the
timestamps from 15 o'clock in the third time interval, which no longer
falls within the sub-section T3 and the battery cells 141 does not
limited with any charging condition, the battery cells 141 will be
allowed to be charged to 100% FCC, if the case, since 15 o'clock.

[0028] There are other intersections in FIG. 3. For example, a sub-section
T4 of the first time interval and a sub-section T5 of the
second time interval get an intersection including 4 consecutive
timestamps from 20 o'clock to 23 o'clock. According to the invention, the
control unit 12 limits the power supply unit to charge the battery cells
141 to not exceeding 80% of the FCC at a sub-section T6 of the third
time interval (day 3) that corresponds to the intersection and includes 4
consecutive timestamps from 20-23. It also should be noted that the 0
index in each timestamp during 20 o'clock and 23 o'clock of the third
time interval means the battery cells 141 have been charged to the
limited FCC, or 80% of the FCC for example, as mentioned earlier.
Likewise, a sub-section T7 of a fourth time interval (day 4) and a
sub-section T8 of a fifth time interval (day 5) are being analyzed
for intersection of the sub-sections to be referred to by the control
unit 12 for further charging limitation as carried out previously. There
are still some intersections in this figure that are not circled out but
can be used by the control unit 12 for carrying out the charging control,
description about which is omitted here for brevity.

[0029] Additionally, the charging control method 100 provided by the
invention describes its mechanism by using two preceding time intervals
to output the intersection of sub-sections with FCC and determining the
charging control of the battery for the next time interval. However,
three or more preceding time intervals for analysis of the intersection
of sub-sections in need are also available in the invention. The
embodiments described in the previous paragraphs should not form a
limitation regarding the number of time intervals to be analyzed. Also
the specific proportion, say 80%, of the FCC in the embodiment is also
for exemplary purpose and should not be regarded as a limitation.
Furthermore, for practical implementation and efficiency consideration, a
sub-section retrieved in each time interval should at least include two
consecutive hours/timestamps that have the RSOC of the rechargeable
battery in the FCC, which means n should be a positive integer at least
larger than 1 for any sub-section including n consecutive timestamps, and
preferably n is a positive integer larger than 3 and smaller 24 to
generate practical sub-sections.

[0030] By analyzing consecutive timestamps at which the battery cell is
fully charged in two or more previous time intervals, the charging
control method utilizes these consecutive timestamps of a sub-section of
each time interval as a charging control way to the rechargeable battery
in a present time interval. The charging process of the rechargeable
battery in corresponding timestamps of the present time interval is
limited to a specific proportion of the fully charged capacity of the
battery cells. In such way, the rechargeable battery may have fewer
chances to be fully charged at some less used time, which substantially
increases the life of the battery.

[0031] Those skilled in the art will readily observe that numerous
modifications and alterations of the device and method may be made while
retaining the teachings of the invention. Accordingly, the above
disclosure should be construed as limited only by the metes and bounds of
the appended claims.

Patent applications by Kuo-Chang Huang, Hsinchu County TW

Patent applications by Tai-Hung Chen, Hsinchu County TW

Patent applications in class With detection of current or voltage amplitude

Patent applications in all subclasses With detection of current or voltage amplitude